Preheat the oven to 350 degrees F (175 degrees C). Grease and flour a 9x13-inch baking pan.

Sift flour and baking powder together; set aside.

Beat sugar and butter together in a large bowl with an electric mixer until light and fluffy. Add eggs and vanilla; beat well. Add flour mixture, about 1/2 cup at a time, mixing until well blended. Pour batter into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 30 minutes. Pierce cake all over with a fork; let cool to room temperature.

Mix whole milk, condensed milk, and evaporated milk together in a bowl; pour over the top of the cooled cake and allow to soak in.

Whip cream, remaining 1 cup of sugar, and 1 teaspoon vanilla in a chilled glass or metal bowl with an electric mixer until thick. Spread over the top of the filling. Keep cake refrigerated until serving.